1. Field of the Invention
The invention relates to an extension arm, particularly a pivotable and inclinable extension arm, for a supporting system, for the suspended attachment of preferably medical devices.
2. Discussion of the Prior Art
A known extension arm comprises a horizontal or spring arm, which is attached by means of a connecting piece of the extension arm to a ceiling mount which is preferably mounted on the ceiling of a room in which the devices are used. Here, the connecting piece is connected to the horizontal arm by way of a hinge joint, so that the horizontal arm can be inclined relative to the connecting piece with respect to the horizontal. Moreover, the extension arm has an attachment piece which is connected by means of a joint piece to the horizontal arm and on which for example medical equipment, such as an operating light or a protective X-ray shield may be attached. In order to enable a plurality of different devices to be attached to the extension arm, the connection is designed to be releasable, which means that it is necessary to secure the connection in order to prevent the connection from being released unintentionally. The known securing means has a securing element which engages in a groove in the connecting element connected to the device, thus blocking withdrawal of the connecting element from the attachment piece. Here, the connection is designed in such a way that part of the weight of the device acts on the securing element in the assembled condition.
The known extension arm has a plurality of disadvantages. In the course of time, the securing element can escape from the groove with the result that it now engages only partially in the groove and the securing force is considerably reduced in the event of maloperation. If the securing element engages only partially in the groove, the problem moreover arises thatxe2x80x94if the device to be attached is very heavyxe2x80x94the load from only part of the weight of the device is sufficient to bend the securing element or damage the connecting element in the region of the groove as a result of the load on the securing element in the region of the groove in the connecting element. During dismantling, e.g. dismantling for the purpose of attaching another medical device, this can also result in it no longer being possible to remove the securing element from the groove in the connecting elementxe2x80x94or it only being possible to remove it with difficultyxe2x80x94with the result that substantial repair measures are required. There is moreover a risk of the securing element not engaging evenly in the groove in the connecting element, with the result that the securing force is relatively small and the problems discussed above arise accordingly.
The object of the invention, therefore, is to provide an extension arm in which the functionability of the securing mechanism is ensured and, in particular, the cooperation between the securing element and the connecting element is improved, and furthermore to devise a process by means of which this secure connection can be produced.
The object is achieved by an extension arm in which a spring element is pushed at least partially between a securing bushing and the securing element. Furthermore, there is also provided a method for assembling a preferably medical device by use of the connecting element on an extension arm.
The extension arm according to the invention is advantageous in that the securing element for securing the attachment of the connecting element on the attachment piece is held in the groove of the connecting element by the spring element, thus achieving a reliable securing action whereby the securing element is prevented from escaping from the groove in the connecting element and an uneven load on the securing element in the region of the groove is avoided, with the result that the extension arm is more secure and is particularly suitable for relatively great weights, i.e. for heavy devices, acting on the attachment piece.
Advantageous further developments of the extension arm described in the detailed description as set forth hereinbelow.
At least one securing screw is advantageously provided, which is screwed into the securing bush and on which the spring element is at least partially supported. Thus, the pre-tension force of the spring element can be adjusted and particularly additionally increased, the securing screw additionally being acted upon by a spring force from the spring element, so that the securing element is additionally prevented from being released unintentionally.
It is advantageous that the securing screw cooperates with the securing element to block a displacement of the securing bush relative to the securing element. This prevents the securing bush from being displaced with respect to the attachment piece in such a way that the securing element and/or further securing or attachment means, e.g. a cylinder pin, are not secured.
It is advantageous that the securing bush has a cutout in which the securing element and the spring element are partially arranged. Thus, the position of the securing element and/or the position of the spring element can be additionally fixed, so that in particular tilting of the securing element or the spring element in a plane perpendicular to the axis of the attachment piece is prevented.
The spring element is advantageously constructed from a preferably metal spring strip. It is advantageous here that the spring element has a first portion and a second portion which, in a relaxed condition of the spring element, are arranged at least substantially perpendicular to one another. This results in a spring element which is easy to manufacture and which generates a large spring force in the assembled condition of the extension arm.
It is furthermore advantageous that the first portion is longer than the second portion. Thus, the spring element can be advantageously guided in between the securing bush and the securing element and aligned between them. Advantageous alignment of the spring element in the cutout in the securing bush is particularly possible.
It is advantageous that the second portion is constructed to be such a length that it projects at least approximately over the lower edge of the securing bush in the assembled condition of the extension arm. Thus, when assembling the extension arm, it is particularly easy to determine whether the spring element is assembled correctly. This moreover enables the assembly personnel to carry out a simple check as to whether the spring element is installed in order to ensure the security of the extension arm. An essential factor here is that it is not necessary to carry out dismantling procedures in order to check whether the spring element is installed and whether it has been arranged correctly; instead this is possible merely by means of external examination.
The first portion and the second portion are advantageously connected by means of a U-shaped middle portion which abuts at least partially against the securing element. Thus, the assembled position of the spring element is fixed in a direction parallel to the axis of the attachment piece, thus further simplifying assembly.
It is furthermore advantageous that at least one securing screw is provided, which is screwed into the securing bush and engages at least partially in the U-shaped middle portion of the spring element. Thus, the spring element is additionally secured, the securing bush moreover being secured against displacement in a direction along the axis of the attachment piece.
The inventive process as described herein is advantageous in that the securing element is pushed particularly deep into the groove in the connecting element in that the securing spring is pushed in between the securing bush and the securing element, the securing element additionally being acted upon by a holding force in that the securing spring is pre-tensioned by means of the securing bush as a result of displacing this latter along the attachment piece.
Advantageous further developments of the process are described in further detailed hereinbelow.
It is advantageous that a securing screw is furthermore screwed into the securing bush in order to block displacement of the securing bush and additionally tension the securing spring.
It is moreover advantageous that the connecting means connecting the connecting element to the attachment piece is inserted through an opening in the securing bush.